Internal combustion engines having a compressor for compressing the air supplied to the internal combustion engine are known in the art, e.g., published Japanese patent document JP-2001-123844 describes a method for diagnosing an electric booster compressor, whereby a plausibility check is performed on the rotational speed signals of the electric booster compressor. An error is deduced if the actual rotational speed of the electric booster compressor deviates from the setpoint rotational speed for more than a certain period of time despite the rotational speed regulation.
Published German patent document DE 101 24 543 describes a method for controlling an electrically operated supercharger that cooperates with an exhaust gas turbocharger, in particular how a setpoint pressure ratio, referred to here as vpsoll, and an actual pressure ratio, referred to here as vpist, across electrically operated supercharger 5 are determined. Actual pressure ratio vpist may be modeled on the basis of the engine speed and the mass air flow rate measured by mass air flow meter 40 with the aid of an engine characteristics map, and as a function of the ambient pressure measured by ambient pressure sensor 30 and the boost pressure measured by boost pressure sensor 25. This modeling presupposes that the mass air flow rate measured by mass air flow meter 40 flows completely through first compressor 15. In the case when bypass valve 70 is stuck open, this prerequisite is not met and the air flow through bypass 70 is unknown. In this case, the modeling of the actual pressure ratio is faulty. The modeled actual pressure ratio is also referred to below as vpmod. If, according to published German patent document DE 101 24 543, a setpoint value for the mass air flow rate (determined as a function of a driver's intent and additional operating variables, for example) is used instead of the mass air flow rate measured by mass air flow meter 40, this yields setpoint ratio vpsoll across first compressor 5 instead of modeled actual pressure ratio vpmod. The driver's intent may be determined by a gas pedal (not shown in FIG. 1), the degree of actuation of which is forwarded to engine controller 20 for analysis.
German patent document DE 102 35 891, published on Aug. 14, 2003, describes a defined triggering of electrically operated supercharger as part of an early run-up of the electrically operated supercharger.
Published German patent document DE 197 40 968 discloses that setpoint value mLsetpoint for the mass air flow rate may be determined in the air supply regardless of the driver's intent or the driver's desired torque.